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Abstract:

A display apparatus for displaying multiple view angle images is
provided. The display apparatus comprises a display screen and a
plurality of projectors. Each of the projectors comprises at least a
light source module, a spatial light modulator and a lens. The first view
angle image and second view angle image emitted from each projector are
guided to a first sub-viewing zone and a second sub-viewing zone via a
first light beam and second light beam, respectively. The sub-viewing
zones imaged by each projector are adjacent to each other along a
transverse axis sequentially.

Claims:

1. A display apparatus for displaying multiple view angle images,
comprising: a display screen; a plurality of projectors, each of the
projectors comprising: at least a light source module, comprising: a
first light emitting diode (LED) light source, providing a first light
beam according to a first time sequence; a second LED light source, being
adjacent to the first LED light source and providing a second light beam
according to a second time sequence; a spatial light modulator,
transforming the first light beam and the second light beam into a first
view angle image and a second view angle image respectively; and a lens,
projecting the first and second view angle images to the display screen;
wherein light from the first view angle image and light from the second
view angle image projected from each of the projectors are guided to a
first sub-viewing zone and a second sub-viewing zone by the display
screen via the first light beam and the second light beam respectively,
and the sub-viewing zones imaged by each of the projectors are adjacent
to each other along a horizontal axis sequentially.

2. The display apparatus of claim 1, wherein each of the first
sub-viewing zones and each of the second sub-viewing zones are formed on
a reference plane.

3. The display apparatus of claim 1, wherein the at least a light source
module further comprises a third LED light source adjacent to the second
LED light source, the third LED light source emits a third light beam
according to a third time sequence, the spatial light modulator
transforms the third light beam into a third view angle image, the lens
projects the third view angle image to the display screen, and light from
the third view angle image is guided to a third sub-viewing zone by the
display screen via the third light beam.

4. The display apparatus of claim 3, wherein each of the first
sub-viewing zones, each of the second sub-viewing zones and each of the
third sub-viewing zones are formed on a reference plane.

5. The display apparatus of claim 1, wherein the projectors are disposed
in an array.

6. The display apparatus of claim 5, wherein the array comprises a top
row and a bottom row, and the projectors are alternately disposed on the
top row and the bottom row.

8. The display apparatus of claim 7, wherein the display screen further
comprises a vertical diffuser to diffuse the first light beam and the
second light beam in a vertical direction.

9. The display apparatus of claim 1, wherein the display screen comprises
two back-to back lenticular lens sheets and a diffuser layer disposed
between back sides of the two back-to back lenticular sheets.

10. The display apparatus of claim 1, wherein each of the projectors
comprises three light source modules, and the light source modules emit a
first color light, a second color light and a third color light
respectively.

11. The display apparatus of claim 10, wherein the first color light is
red, the second color light is green, and the third color light is blue.

Description:

[0001] This application claims priority to Taiwan Patent Application No.
099115775 filed on May 18, 2010, the disclosures of which are
incorporated by reference herein in their entirety.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0002] Not applicable.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention provides a display apparatus for displaying
multiple images of multiple view angles. More particularly, the present
invention provides a display apparatus with a light emitting diode (LED)
based projector array, which can auto-stereoscopically display multiple
view angle images by using a combination of both a spatial multiplex
method and a time multiplex method.

[0005] 2. Descriptions of the Related Art

[0006] Over recent years, stereoscopic display technology, subsequent to
flat-panel display technologies, has become one of the most important
technologies that are under development. Nowadays, many three-dimensional
(3D) stereoscopic displays that have been disclosed can already be
utilized without wearing special glasses. The principle is to divide the
visual space into a plurality of vertical viewing zones and send two
stereoscopic images to the eyes of the user. Then, according to the
visual characteristics of human eyes, the user can experience the
gradation and depth of field that results in the perception of a 3D image
when the eyes of the user receive two images with the same image content
but different parallaxes.

[0007] FIG. 1 is a schematic view of a conventional projection-type
stereoscopic display apparatus 1 using spatial multiplex method. As shown
in FIG. 1, the conventional projection-type stereoscopic display
apparatus 1 using the spatial multiplex method comprises a plurality of
light sources 11, a plurality of collimating lenses 13, a plurality of
converging lenses 14, a liquid crystal panel 15, a double lenticular lens
17, which comprises two back-to-back lenticular lens sheets, and a
scatter plate 19. Firstly, the light generated by the light sources 11 is
made into collimated light rays via the collimating lenses 13, then an
image is displayed by the liquid crystal panel 15, converged by the
converging lenses 14, and projected onto the double lenticular lens 17.
Herein, two sides of the scatter plate 19 respectively adjoin the double
lenticular lens 17 so that the image can be scattered and projected onto
the viewing zones.

[0008] Additionally, because one projector lens only corresponds to a view
angle, the amount of view angles is limited by the space arrangement of
the projection apparatus, so that the number of view angles of the
aforesaid conventional stereoscopic image display technology is limited.

[0009]FIG. 2 is a schematic view of a conventional projection-type
stereoscopic image display apparatus 2 using time multiplex method. As
shown in FIG. 2, the stereoscopic display apparatus 2 comprises a light
source 21, a polarizer 23, a rotary polygonal mirror 25, a liquid crystal
panel 27 and a number of optical components 29. The light beam generated
by the light source 21 is polarized by the polarizer 23, and then the
polarized light beam is reflected by the rotary polygonal mirror 25 for
scanning An image is displayed by the liquid crystal panel 27 and
projected onto a viewing zone by the optical components 29. The aperture
of the lens is divided into vertical lines. Corresponding to the scanning
of the light source, the lines of light source are scanning Different
lines are guided into different view zones. However, the reliability of
this type of the stereoscopic display apparatus 2 is poor due to the
mechanical rotation of the rotary polygonal mirror 25, which results in
high frictional noises and has constrained rotational speed.

[0010] According to the above descriptions, the aforesaid technologies in
the prior art, no matter using the spatial multiplex method or using the
time multiplex method for displaying the stereoscopic images, have
shortcomings to be overcome. In view of this, a stereoscopic image
display apparatus featuring a simple manufacturing process, high color
saturation and a preferable resolution is an important issue in the
display industry.

SUMMARY OF THE INVENTION

[0011] To solve the aforesaid problems, the objective of the present
invention is to provide a display apparatus for displaying images with
multiple view angles, which can demonstrate a stereoscopic performance of
displaying multiple view angle images by combining the advantages of the
spatial multiplex method and the time multiplex method.

[0012] To achieve the aforesaid objective, the present invention provides
a display apparatus for displaying multiple view angle images. The
display apparatus comprises a display screen and a plurality of
projectors. Each of the projectors comprises at least a light source
module, a spatial light modulator and a lens. Each of the light source
module has a first LED light source and a second LED light source. The
first LED light source provides a first light beam according to the first
time sequence; the second LED light source is adjacent to the first LED
light source and provides a second light beam according to the second
time sequence; the spatial light modulator transforms the first light
beam and the second light beam into a first view angle image and a second
view angle image respectively; and the lens projects the first and the
second view angle images to the display screen. Light from the first view
angle image and light from the second view angle image projected from
each of the projectors are guided to the first sub-viewing zone and the
second sub-viewing zone by the display screen via the first light beam
and the second light beam respectively, and the sub-viewing zones imaged
by each of the projectors are adjacent to each other along the horizontal
axis sequentially.

[0013] With the aforesaid arrangement of the present invention, the
display apparatus can combine the advantages of both the spatial
multiplex method and the time multiplex method to demonstrate a
stereoscopic performance of displaying the images with multiple view
angles and to significantly improve the visual luminance of the display
panel. Furthermore, the use of the LED light sources not only
significantly decreases the volume and power consumption of the
projectors, but also improves the resolution, service life and stability
of the projectors.

[0014] Thereby, a satisfactory stereoscopic displaying effect can be
presented to the user's eyes directly. Thus, the problem with the prior
art is effectively solved.

[0015] The detailed technology and preferred embodiments implemented for
the subject invention are described in the following paragraphs
accompanying the appended drawings for people skilled in this field to
well appreciate the features of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a schematic view of a conventional display apparatus
using spatial multiplex method;

[0017]FIG. 2 is a schematic view of a conventional display apparatus
using time multiplex method;

[0018]FIG. 3 is a perspective view illustrating architecture of an
auto-stereoscopic display according to the first embodiment of the
present invention;

[0019] FIG. 4 is a schematic view illustrating a structure of a projector
according to the first embodiment of the present invention;

[0020] FIG. 5 is a partial top view of the display apparatus in which
Fresnel lens is used as the screen according to the first embodiment of
the present invention;

[0021] FIG. 6 is a schematic view illustrating the light distribution of
the viewing angle image formed by the light source module shown in FIG.
4;

[0022] FIG. 7 is a schematic view illustrating internal components of the
projector of the present invention;

[0023] FIG. 8 is a schematic view illustrating the structure of 3-LED
light source module; and

[0024] FIG. 9 is a schematic view illustrating the light distribution of
the viewing angle images formed by the light source module shown in FIG.
8; and

[0025] FIG. 10 is a partial top view of a display apparatus in which the
double lenticular lens sheets are used as the screen according to the
second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0026] In the following description, the display apparatus of the present
invention will be explained with reference to embodiments thereof.
However, these embodiments are not intended to limit the present
invention to any specific environment, applications or particular
implementations described in these embodiments. Therefore, the
description of these embodiments is only for the purpose of illustration
rather than limitation of the present invention.

[0027] First, FIG. 3 illustrates a perspective view of the architecture of
a display apparatus 3 according to the first embodiment of the present
invention. The display apparatus 3 comprises a display screen 31, a
plurality of projectors 33 and two flat mirrors 35 for reflecting light
beams. The projectors 33 are disposed with respect to the display screen
31 and formed an array in the horizontal direction. In this embodiment,
the array of the projectors 33 has two rows in the vertical direction,
and the projectors 33 are arranged alternately in the two rows to ensure
that the external pupils of the lenses of the projectors 33 adjoin to
completely cover the viewing zone. In this embodiment, fifteen projectors
33 are used; however, this number is only provided for illustration, and
the examples in which the different numbers of projectors 33 are used
will readily occur to those skilled in the art.

[0028] To describe the details of the display apparatus 3 according to the
present invention more clearly, reference will be made to FIGS. 4 to 6 in
the following description.

[0029] FIG. 4 is a schematic view illustrating the internal components of
the projector 33 according to the first embodiment of the present
invention. As can be seen, the projector 33 of the first embodiment
mainly comprises three light source modules, a color combining element
42, a first lens array set 43, a second lens array set 44, a spatial
light modulating element 45 and a lens 47. The three light source modules
comprises a first light source module 41, a second light source module 46
and a third light source module 48. The first light source module 41
comprises a first light emitting diode (LED) light source 41a and a
second LED light source 41b adjacent to the first LED light source 41a;
the second light source module 46 comprises a first LED light source 46a
and a second LED light source 46b adjacent to the first LED light source
46a; and the third light source module 48 comprises a first LED light
source 48a and a second LED light source 48b adjacent to the first LED
light source 48a.

[0030] Each of the light source modules respectively emits a first color
light, a second color light and a third color light. More specifically,
the first and the second LED light sources 41a, 41b of the first light
source module 41 emit the first color light; the first and the second LED
light sources 46a, 46b of the second light source module 46 emit the
second color light; and the first and the second LED light sources 48a,
48b of the third light source module 48 emit the third color light. In
this embodiment, the first color light, the second color light and the
third color light can be a red light, a green light and a blue light
respectively, although the present invention is not merely limited
thereto.

[0031] Each of the first LED light sources 41a, 46a, 48a provides a first
light beam according to the first time sequence; and each of the second
LED light sources 41b, 46b, 48b provides a second light beam according to
the second time sequence. Hence, three first light beams are generated by
the light source modules 41, 46, 48 according to the first time sequence
in turn, and three second light beams are generated by the light source
modules 41, 46, 48 according to the second time sequence in turn. It
shall be appreciated that for the purpose of the clarity of the drawings
and simplicity of the description, only the light paths of the first and
the second light beams of the first light source module 41 are depicted,
with those of the light beams of the second light source module 46 and
the third light source module 48 being omitted; however, those light
paths will be readily known by those skilled in the art.

[0032] In this example, an X-cube is used as the color combining element
42 for combining the red light, the green light and the blue light. In
other examples, the color combining element may also be an X-plate, a
diachronic Mirror or the like, and the present invention is not merely
limited to what is described above.

[0033] After being combined, the first light beams and the second light
beams of three colors pass through the first lens array set 43 and the
second lens array set 44, and are guided into the spatial light modulator
45. The first light beams are transformed into a first view angle image
and the second light beams are transformed into a second view angle image
by the spatial light modulator 45 according to the time sequence. Then,
the lens 47 projects the first view angle image and the second view angle
image onto the display screen 31. In this example, the spatial light
modulator 45 can be a digital micromirror device (DMD); however, in other
applications, a liquid crystal display (LCD) device may also be used.

[0034] FIG. 5 shows the first embodiment of the present invention and
illustrates a partial top view of the display apparatus 3 in which the
screen of fresnel lens type are used. In the display apparatus 3, the
projectors 33 are arranged in an array. The projectors 33 arranged in the
lower row of the array are omitted from depiction herein for convenience
of description.

[0035] As shown, the display screen 31 comprises a Fresnel lens 51 and a
vertical diffuser 53. The Fresnel lens 51 focuses the light beams from
the projectors 33 onto a plane; and the vertical diffuser 53 diffuses the
first light beams and the second light beams along the vertical direction
to enlarge and extend the vertical viewing zone and mitigate
non-uniformity of the light beams. The images projected by each of the
projectors 33 are guided onto the corresponding viewing zone 52 via the
display screen 31; in other words, fifteen viewing zones 52 will be
generated by the fifteen projectors 33 in this embodiment, and all the
viewing zones 52 are located within an identical reference plane 50.

[0036] To present the imaging status of the viewing zones more clearly,
FIG. 6 depicts the image distribution of the viewing zones 52 on the
reference plane 50. Here, one projector and a corresponding viewing zone
52 will be taken as an example for description. The light from first view
angle image 63a and the light from second view angle image 63b from the
projector are respectively guided to the first and second sub-viewing
zones of 61a and 61b by the display screen 31. The vertical diffuser 53
diffuses the first light beams and the second light beams along the
vertical direction to enlarge and extend the vertical angle images and
forms the first view angle image 63a and second view angle image 63b. The
view angle images generated by all the projectors are adjacent to each
other along the horizontal axis sequentially, and the view angle images
belonging to different sub-viewing zones form the displaying images with
superior stereoscopic resolution. In short, the view angle images
presented in the individual sub-viewing zones of the viewing zones are
different from each other, so that the left and the right eyes of the
user perceive two different view angle images as the two eyes
respectively correspond to two adjacent sub-viewing zones. Thus, a
stereoscopic image performance can be demonstrated. It shall be mentioned
that the display screen 31 can include other optical components with
stereoscopic displaying functions for manipulating the viewing zones
according to practical demands, and the present invention is not limited
to what is described above.

[0037] In this embodiment, a plurality of LED light sources are turned on
and off sequentially to produce a time multiplex effect to generate a
stereoscopic displaying effect of time multiplex by rapidly switching
time sequences. Furthermore, a spatial multiplex effect can be further
achieved by using a number of projectors arranged in an array to improve
the flexibility in the view angle division.

[0038] FIG. 7 is a schematic view illustrating the internal components in
the projector of the present invention. The projector 7 comprises three
light source modules, a beam splitter set 73, a first lens array set 74,
a second lens array set 75, a spatial light modulator 76, a total
internal reflection (TIR) prism 77, a lens 78 and a heat dissipation
module 79.

[0039] As shown in the projector 7 of this example, the three light source
modules include a first light source module 70, a second light source
module 71 and a third light source module 72. The first light source
module 70 comprises a first LED light source 70a and a second LED light
source 70b adjacent to the first LED light source 70a; the second light
source module 71 comprises a first LED light source 71a and a second LED
light source 71b adjacent to the first LED light source 71a; and the
third light source module 72 comprises a first LED light source 72a and a
second LED light source 72b adjacent to the first LED light source 72a.
Herein, the first and the second LED light sources 70a, 70b of the first
light source module 70, the first and the second LED light sources 71a,
71b of the second light source 71 and the first and the second LED light
sources 72a, 72b of the third light source modules 72 are respectively
for emitting the first color light, second color light and third color
light. In this example, the first color light is a red light, the second
color light is a green light, and the third color light is a blue light,
although they are not limited thereto. In this example, the red light,
the green light and the blue light emitted by the LED light sources are
combined by the beam splitter set 73, and then passing through the first
lens array set 74, the second lens array set 75, the spatial light
modulator 76 and the TIR prism 77. Finally, the image is projected
outwards by the lens 78.

[0040] In this example, a heat dissipation module 79 is further provided.
The heat dissipation module 79, which adjoins the light source modules
70, 71, 72 via a heat dissipation plate (not shown), dissipates heat
around the LED light sources 70a, 70b, 71a, 71b, 72a and 72b by a cooling
air flow 69.

[0041] FIG. 8 is a schematic view illustrating the internal components in
yet another example of the present invention, while FIG. 9 is a schematic
view illustrating the light distribution of the sub-viewing zones that
are formed by imaging the exit pupils of the lenses and diffusing the
imaged light in the vertical direction. As shown in FIG. 8, the projector
8 of this example also comprises three light source modules 81, 86, 88, a
light combining element 82, a first lens array set 83, a second lens
array set 84, a spatial light modulator 85 and a lens 87. However, as can
be known by the comparison between FIGS. 8 and 4, the difference between
the light module 8 of this example and the light module 33 of the first
embodiment is that each of the light source modules 81, 86, 88 of the
projector 8 of this example has three LED light sources. In more detail,
the first light source module 81 comprises a first, a second and a third
LED light source 81a, 81b, 81c adjacent to each other; the second light
source module 86 comprises a first, a second and a third LED light source
86a, 86b, 86c adjacent to each other; and the third light source module
88 comprises a first, a second and a third LED light source 88a, 88b, 88c
adjacent to each other.

[0042] The light source modules respectively emit a first color light, a
second color light and a third color light. More specifically, the first,
the second and the third LED light sources 81a, 81b, 81c of the first
light source module 81 are for emitting the first color light. The first,
the second and the third LED light sources 86a, 86b, 86c of the second
light source module 86 are for emitting the second color light. The
first, the second and the third LED light sources 88a, 88b, 88c of the
third light source module 88 are for emitting the third color light.

[0043] In this embodiment, the first color light, the second color light
and the third color light are a red light, a green light and a blue light
respectively, although the present invention is not merely limited
thereto.

[0044] Each of the first LED light sources 81a, 86a, 88a provides a first
light beam according to the first time sequence; each of the second LED
light sources 81b, 86b, 88b provides a second light beam according to the
second time sequence; and each of the third LED light sources 81c, 86c,
88c provides a third light beam according to the third time sequence.
Accordingly, the three first light beams are generated by the light
sources 81a, 86a, 88a in turn according to the first time sequence, the
three second light beams are generated by the light sources 81b, 86b, 88b
in turn according to the second time sequence, and the three third light
beams are generated by the light sources 81c, 86c, 88c in turn according
to the third time sequence. It shall be mentioned that that light paths
of the second light source module 86 and the third light source module 88
are omitted herein, and only the light paths of the first, second and
third light beams of the first light source module 81 are depicted for
the purpose of clarity of the drawings and simplicity of the description;
however, those light paths will be readily known by those skilled in the
art.

[0045] The elements and associated operational mechanisms that are the
same as what is described above will not be further described herein. It
shall be mentioned that the amount of LED light sources of the light
source modules may be increased for forming more corresponding
sub-viewing zones according to the above examples of the projector of the
present invention.

[0046] As shown in FIG. 9, the light source of the third view angle image
is imaged onto a third sub-viewing zone 91c and further diffused and
extended into sub-viewing zone 91c via a display screen (not shown). The
first view angle image 93a and the second view angle image 93b are also
formed and diffused into the sub-viewing zones 91a and 91b in the same
way. The first sub-viewing zones 91a, the second sub-viewing zones 91b
and the third sub-viewing zones 91c are formed on a reference plane 90.

[0047] The second embodiment of the present invention is shown in FIG. 10.
The difference between the second embodiment and the first embodiment is
that the display screen 101 of the display apparatus 10 comprises two
back-to back lenticular lens sheets (also named as "double lenticular
lens sheets"), which has two lenticular lens sheets 101a, 101c and an
all-directions diffuser 101b sandwiched between the two lenticular lens
sheets 101a, 101c. The first Fresnel plate 103a and a second Fresnel
plate 103b can be disposed on the outsides of the two lenticular lens
sheets 101a, 101c when in the case of short throw distance or short
observing distance.

[0048] According to the above descriptions, with the aforesaid particular
combination of the projector array and the display screen, the display
apparatus of the present invention is essentially an auto-stereoscopic
display that formed by LED based projector array. The display apparatus
can combine the advantages of the spatial multiplex method and the time
multiplex method to achieve the auto-stereoscopic function of displaying
multiple view angle images. Furthermore, the used LED light sources can
not only significantly decrease the volume and power consumption of the
projectors, but also improve the resolution, service life and stability
of the projectors. Thus, the problem with the prior art is effectively
solved. With the display apparatus of the present invention, a
stereoscopic image with preferable resolution can be presented to the
user.

[0049] The above disclosure is related to the detailed technical contents
and inventive features thereof. People skilled in this field may proceed
with a variety of modifications and replacements based on the disclosures
and suggestions of the invention as described without departing from the
characteristics thereof. Nevertheless, although such modifications and
replacements are not fully disclosed in the above descriptions, they have
substantially been covered in the following claims as appended.